TAMPA, Fla. — Researchers say the Delta COVID-19 variant is the most contagious one so far.
It's now the dominant strain in the country, and cases are climbing.
The Centers for Disease Control and Prevention say the Delta variant was initially identified in India and now accounts for at least 57.6% of newly confirmed cases in the United States.
"It's more transmissible indoors, it's more transmissible outdoors, it's just more transmissible in general," said Dr. Michael Teng, Virologist and Associate Professor at The University of South Florida.
As more people continue to gather once again, doctors say it's possible to get a breakthrough COVID-19 infection, even if you're fully vaccinated.
"Obviously, the vaccines are not 100%. There are some cases of people getting relative severe infection after getting vaccinated, but this is vanishingly small," said Teng.
The CDC says breakthrough infections are expected and that there will be a small percentage of fully vaccinated people who will get sick, hospitalized, or die from COVID-19.
While still uncommon, experts say these breakthrough cases are more possible with the Delta variant.
"For the vast majority of people who are vaccinated, it's going to be very mild," said Teng.
The Delta strain was first detected in March in the U.S. and can now be found in all 50 states.
The variant has been identified in more than 100 countries and is expected to become the dominant COVID-19 mutation worldwide, according to the World Health Organization.
Experts say the Delta strain is particularly dangerous for unvaccinated and partially vaccinated people.
"The vaccines are great at protecting you from severe disease. Some people may feel symptoms after getting exposed. Some people might not get symptoms. But for unvaccinated people, Delta is a much bigger problem," said Teng.